1. Field of the Invention
This invention relates to methods and systems for neutralizing toxic, explosive, and other potentially harmful gases, and more particularly it relates to such methods and systems for use in connection with oil and gas drilling and production.
2. Description of the Prior Art
There are many industrial facilities where toxic and explosive gases necessarily escape with consequent danger to personnel, pollution of the environment, and possible destructive explosion and fire. This is particularly a problem around oil and gas drilling rigs and oil and gas production facilities. Numerous fires and explosions have occurred on drilling rigs and production facilities with resulting injury and death to personnel and destruction of property. Although it is often difficult to fix the precise blame for such fires and explosions, it is apparent that in any such instance flammable vapors and gases must have been present. One situation which is particularly hazardous because of the presence of such flammable vapors and gases, as well as other toxic gases, is that of the offshore drilling platform, which has numerous enclosed and partially enclosed areas which can act as gathering places for explosive and toxic mixtures of gases. Such gases are necessarily produced during the drilling operation, and are carried to the surface in solution in the drilling fluid. When the drilling fluid reaches the surface, decreased pressures allow the escape of some gas. Other gases are purposely removed by degassing equipment so as to raise the specific gravity of the drilling fluid. Such gases usually consist primarily of methane, although other low-boiling hydrocarbons, such as ethane and propane, are usually also present, and sulfur-containing compounds, such as hydrogen sulfide, mercaptans and sulfur oxides, are also sometimes present.
In the past it has not been possible to gather and dispose of such gas in a manner which will insure protection from the possible harmful effects of the gas.
On the same offshore platforms (as well as in other industrial operations where toxic and explosive gases may escape) various hydrocarbon fuel energy generators are usually also present. Such energy generators, as, for example, gas engines and diesel engines, emit exhaust which contain, among other things, carbon monoxide, carbon dioxide, water vapor, unburned and partially oxidized hydrocarbons, nitrogen oxides, and other undesirable gases which will pollute the atmosphere. These gases also tend to accumulate in enclosed and partially enclosed areas. Methods have heretofore been devised to render these exhaust gases inert by reacting them in the presence of an oxidation catalyst to produce primarily nitrogen, carbon dioxide and water. Such methods are described, for example, in U.S. Pat. Nos. 3,000,707 to Barstow, 3,232,885 to the present inventor, and 3,579,308 to Gower.
To combat the accumulation of undesirable gases it has heretofore been the practice to utilize large fans to blow the gases away from areas such as an offshore platform. However, this method does not insure that all of the undesirable gases are removed from the platform, and wind, humidity and other atmospheric conditions may cause the unwanted gas to merely be transported to various corners and crannies where it may collect in high toxic or flammable concentrations. It is impractical to collect and burn the gases because the flow is generally intermittent and the mixtures of air and gas that are collected could not be depended upon to have the proper air to fuel ratio to sustain combustion.
Hydrogen sulfide is a common ingredient gas which is produced with drilling fluid. This gas is extremely toxic, even small amounts being deadly, so that the dispersing of this gas in areas where personnel are working creates an extremely dangerous and hazardous condition.
In the drilling of oil wells, sometimes gas pockets are encountered by the drill and a large high pressure gas bubble is released so that it passes up the well with the drilling fluid. This gas bubble, called a "kick" in the field, produces an extremely large volume of gas in a short period of time, which gas must be disposed of in such a way as to avoid endangering personnel and equipment.